New York State IPM Program

May 16, 2017
by Mary M. Woodsen
Comments Off on Keep Off the Grass? IPM for Anyone With a Lawnmower

Keep Off the Grass? IPM for Anyone With a Lawnmower

Now that spring has arrived and you’ve dusted off the lawn mower …

As a kid of about five, I became suspicious of lawns. In a rare moment of TV viewing, I had seen a public-service ad wherein a bundle of green leafy stuff thudded into an eerily vacant playground while a baritone voice boomed out something like “Grass. We think it’s bad for kids. Stay away from it.” My mom insisted this was “bad grass” which did not grow in our yard. However, she declined to elaborate, which fueled my mistrust. So I kept off the lawn a while.

These days, “bread” is no longer money, “mint” is just a flavor, and the pernicious leafy stuff mostly goes by other names. There is only one grass, and it is almost time to cut it again. Jargon may change, but things like paying taxes and mowing lawns don’t seem to.

To help you, or so they say, a bewildering array of lawn-care products have sprouted at big-box stores and garden centers. It’s easy to spend a lot of dough — I mean money — on fertilizers, weed killers, and seed. But it’s hard to make sense of which products are right for you.

Before you shop, a couple of thoughts to help sort things out.

  • Grass is not for everyone. Or everywhere. If an area does not get 4 or more hours of full sun daily from March through September, trying to grow grass there is a waste of time.
  • Steep slopes and high-traffic zones probably need something other than grass, too.

Keep mower blades sharp — it can help reduce disease, plus it looks nicer and saves on mower gas. (Flickr Creative Commons Brian Boucheron)

Comparison spells trouble. Well not literally, but it’s mighty unfair. Fashion models have airbrush artists and makeup consultants. Golf courses have full-time turf experts and a massive budget. With good information and a little work, we and our lawns can both look good, but let’s not compare with deep-pocketed pros.

Dr. Frank Rossi, a leading Cornell Turfgrass Science researcher, puts it this way:

“Chances are you can grow a pretty good lawn without using insecticides, fungicides, or herbicides. You may even be able to do it using little or no chemical fertilizer… Will your lawn look like a putting green? No… But if you arm yourself with an understanding of what grasses need to thrive, and commit to a long-term plan to meet those needs, you can grow a perfectly acceptable lawn…”

Get the dirt on your soil. If your grass looks bedraggled, fertilizer may not be the answer; in fact, early-season nitrogen can weaken grass and make lawns worse in the long run.

At the very least, get a soil pH test—a pH more acidic (lower) than 6.0, or more alkaline (higher) than 7.0 will hinder plants’ ability to absorb nutrients. The majority of samples I get at the office have pH values too high for healthy lawns, sometimes 100 or even 1,000 times too alkaline due to annual lime treatments. Lime is only good if it’s needed.

If it’s been over three years since the soil was tested, you might want to invest in a lab analysis. For under twenty bucks you can get nutrient levels with specific recommendations, plus pH and salt content. This last item may seem odd, but fertilizers, herbicides, wood ash and deicing agents are all sources of salt — which can damage soil structure, harm microbes, and aggravate water stress.

Only fertilize based on soil test results, and only use nitrogen in the fall.

Nature abhors a vacuum, which is why I keep mine hidden away indoors — no sense offending nature if you can avoid it. This hatred of emptiness means that if you don’t re-seed bare or weak spots in the lawn, Nature will fill it with whatever is handy — probably weeds.

Edging along the sidewalk or driveway may produce the look you want, but it also produces a lot of bare earth, so if you have a weed issue, especially crabgrass, breaking this habit will give you an edge on weed control.

Another type of vacuum is a close-cropped lawn. Not only does close mowing cause weak, stunted grass roots (and thus plants), it allows the sun full access to the soil. This gives weeds a tremendous advantage.

Have trouble with ground ivy? Put away the vacuum. Stop shaving the earth and start mowing the grass.

The most important thing you can give your lawn is more of its hair. Studies show that changing to a grass height of 3.5 inches leads to a vast improvement in lawn health. Leaving grass longer will greatly reduce weed pressure, lawn diseases, and fertilizer requirements. Perhaps the most dramatic change with longer grass is a lasting drop in weed population.

If you need to use herbicides to reduce weeds, follow the label instructions closely. Some broadleaf (selective) herbicides contain chemicals that could stress or injure trees. Pre-emergent herbicides inhibit weed germination, and are used for crabgrass control. Apply pre-emergent products around the time forsythia flowers are starting to drop.

Another tip is not to mow more than a third of the grass at a time. For example, to maintain a 3.5-inch turf height, mow before the grass gets over five inches high. Try to keep the blades sharp — it can help reduce disease, plus it looks nicer and saves on mower gas. And it almost goes without saying that grass clippings belong to the lawn, not the landfill. Leave the clippings—that’s your fertilizer.

White grubs — we have five species in northern NY — can become a problem if there are more than ten per square foot of lawn. Several nontoxic and low-toxicity treatments have come on the market in the past few years, but timing varies for all of them. Milky spore treatment is safe, but is not effective up north due to cool soils. You can also use beneficial nematodes to kill grubs. 

There are many solid lawn-care resources out there, but always check the source, which should be from .edu or .gov sites. Cornell Senior Extension Associate Lori Brewer has assembled the work of many experts, including Dr. Rossi, into a comprehensive 47-page book entitled “Lawn Care,” which is free at http://hort.cornell.edu/turf/lawn-care.pdf

I think it will contribute to a better world if we teach our kids to stay grounded and let the grass get high.

See more at Morning Ag Clips.

These nematodes Hetzler mentions — beneficial organisms — are key to good IPM. In fact, good IPM embraces every concept Hetzler stands by. With IPM, prevention is always the best cure. And remember: even herbicides are a type of pesticide, because weeds are pests too. If you’ve ever spent a whole day weeding a not-that-big garden, you know that sometimes weeds are the most difficult contenders we face. — ed. MW.

September 21, 2016
by Mary M. Woodsen
Comments Off on Trees and Drought Make for Less Colorful Fall (and the IPM Connection)

Trees and Drought Make for Less Colorful Fall (and the IPM Connection)

Many thanks to Paul Hetzler, CCE St. Lawrence County, for permission to use this piece.

It turns out that, in terms of fall foliage, the color of too dry is officially known as “blah.” This would undoubtedly be the least popular color selection if it was included in a jumbo pack of Crayolas. Basically, it is a jumble of faded hues with a mottled brown patina throughout. This year’s dry summer could mean that “blah” may feature prominently in Mother Nature’s fall hardwood forest palette.

Why would a prolonged lack of moisture affect autumn color? Let’s look at what makes leaves colorful in the first place. Among the things we learned — and probably forgot right away — in Junior High Biology is that leaves are green because of chlorophyll, the amazing molecule that converts light, water and carbon dioxide into sugar and oxygen. Its intense green tends to mask colors such as orange and yellow that are present in leaves in lower concentrations. When chlorophyll dies off in the fall, those “weaker” colors are revealed.

The Adirondacks in full autumnal glory — but not in the mega-drought of 2016.

The Adirondacks in full autumnal glory — but not in the mega-drought of 2016. Photo courtesy Sharp Swan.

It’s not like yellow and orange are just randomly painted on the insides of leaves, though. Molecules other than chlorophyll are involved in various metabolic pathways within a leaf, and they happen to be colorful. By comparison, we are boring. Our hemoglobin is red, at least in the presence of oxygen, but we are not as flamboyant on a cellular level as leaves are.

Red, however, is a horse of a different color where leaves are concerned. Trees spend energy that they would otherwise save for next year’s growth to make the molecule responsible for red. It is called anthocyanin, mostly because short words embarrass scientists, and it is “expensive” for trees to make. No one knows why trees do this. OK, there are some explanations out there, but they are so flimsy they don’t even hold up in the rain.

In wintertime, I make my own bread. Although quality varies because I never use a recipe, more than likely the bread would turn out worse than usual if I omitted water. Similarly, all the ingredients need to be there for photosynthesis to work properly. When water is in short supply, production at the sugar factory, also known as the chlorophyll molecule, drops off sharply.

Without sugars, many cellular processes slow or even stop. Damaged chlorophyll is not replaced, and that deep forest-green color starts to pale. Those yellow and orange molecules (xanthophylls and carotenes, if you are insecure about word length) also begin to disappear.

As trees dry out further, their leaves start to brown along their edges. This is called marginal scorching, not to be confused with marginally scorched, which describes my bread. In drought-prone locations with thin soils, some tree leaves will entirely brown and turn crisp, calling it quits for the year. This of course is not good for trees, because they are not able to plug up the vascular connections between leaves and twigs, making them prone to even more desiccation over the winter.

As if that isn’t enough sepia tones for one season, our sugar maples once again are looking tawdry due to yet another infestation of the native maple leafcutter. This is a tiny colorful moth whose newly hatched larvae eat circular patterns inside leaves, eventually getting big enough to emerge onto the leaf surface and excise little holes in it to make a mini turtle-shell case for itself. A single infestation causes only minor harm to the maples, but repeated infestations can weaken them somewhat.

Between marginal scorch, brown leaves, holey maples and a general shortage of leaf pigments, we might not get the brightest display this fall. Cool nights and sunny days tend to favor the production of red in the few tree species capable of producing it, and this could at least offset the brown tinge that infuses our woodlands at present. Here’s hoping for a good crayon selection this autumn.

The IPM Connection? Well, you can’t run the well dry trying to keep your trees happy. But worse yet would be thinking your trees have some horrid disease and it’s time to dash over to the garden center for a jug of fungicide. In this case you’ve got two fundamental IPM precepts to guide you now and for the future: an accurate diagnosis and preventive action.

  • Identify (i.e. diagnose) your problem before you act. Trees that look sick or pest-ridden could suffer instead from to a surfeit or lack of three critical things their fine feeder roots need: the oxygen, water, and nutrients. Because if those roots aren’t happy, neither is your tree.
  • Prevent the problem: learn which trees will work for your landscape and how to help them deal with the hand Nature deals them. Right plant, right place, proper care: these help reduce infestations and impacts of pests.

Check out this helpful guide.

November 21, 2014
by Mary M. Woodsen
Comments Off on DIY “Strip-Trials” for IPM On-Farm Research

DIY “Strip-Trials” for IPM On-Farm Research

Field corn is the king of crops in New York. This highest net-value and most widely grown crop occupies more than a million acres statewide. Some years it’s hammered by leaf blights that can cost considerably if not treated in time. Other years your crops get off almost unscathed. So — how to know which conditions tip the scales for health or disease on your farm — and thus whether you should spray or put that money to a different use?

Just because you needed a fungicide one year doesn't mean you will the next. Photo credit: G. Bergstrom, Cornell University

Just because you needed a fungicide one year doesn’t mean you will the next. Photo credit: G. Bergstrom, Cornell University

A savvy farmer who knows the risks and benefits of pesticides needs ways to tell if a given fungicide will provide higher yields and profits, and under what conditions. To help, IPM researchers have taught and tested new materials that guide growers in setting up side-by-side strip trials — three or more pairs of treated and untreated corn, each strip at least 10 feet wide, so you can do your own on-farm research.

For if good judgment is the best IPM tool a farmer has, the best place to hone it is in your own fields, under your growing conditions. There’s no better way to know which combination of best-management tactics work best in the microcosm known as your farm — regardless what a specialist or salesperson might say.

Find these new protocols and their companion data sheets on our website. (Hint: both are links to pdfs.)

Special thanks to Professor Gary Bergstrom, Field Crops Pathology Extension Program, Cornell University

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